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of the area. The minimum annual rainfall of the region is about thirty 

 inches, and the run-off may, in dry years, fall as low as t\A'enty-five per 

 cent, of the rainfall. In the eastern region (Knobstone fnrniation i water 

 for municipal supply will have to be impounded, except where the under- 

 liow of the larger valleys may be usetl ; and the conditions for building 

 dams are Ideal. In the central portion of the area the rock substratum is 

 evei'y where very cavernous and leaky, and tight ponds will be dilHcult t > 

 obtain. A few of the larger springs furnish sufficient water for small 

 cities without inipunnding. All deep wells produce niiut'ral water, and 

 shallow wells are inadequate. In tlie western portion the conditions are 

 iutermetliate between those of the eastern and central portions. To main- 

 tain the perennial tlow of springs and ]irevent the silting of ponds the 

 steep slopes of the area should ]»e reforested, where neces.sary, and for 

 ever kept in forest. 

 Geological Lahoratory, 

 I n dill n a Uti ivcrsiliJ. 



